The expanding evidence for the efficacy of ACT: results from a meta analysis on clinical applications

Earlier meta analysis Hayes et al 2006 Ost, 2008 Powers et al, 2009 Veehof at al, 2011 Ruiz, 2012

For Cohen's d an effect size of 0.2 to 0.3 might be a "small" effect, around 0.5 a "medium" effect and 0.8 to infinity, a "large" effect

Hayes et al 2006 Until spring 2005 the meta-analysis examines the average relationship between the AAQ or its specific variants and measures of psychopathology and quality of life. And, a simple version of outcome analysis 17 studies, N=704

Criteria for inclusion RCT articles and any other available data set (dissertation, paper) Levitt, 2004 is not a treatment study Acceptance based

Results weighting average effect sizes by the number of cases that produced the effect ACT compared to general control conditions (9 studies): post: d =.66 (N=704) FU: d =.66 (N=519) Comparisons between ACT and structured interventions (12 studies): post: d =.48 (N=456) FU: d =.63 (N=404) comparisons between ACT and C(B)T (4 studies): d =.73 at post and d =.83 at FU

Overlap with other MA 12 studies included in Ost 12 studies included in Powers 1 study included in Veehof 5 studies included in Ruiz 8 studies included in A-Tjak

Öst, 2008 from 1985 to mid 2007 ACT and other third wave therapies Complicated system of matching studies of ACT to studies of CBT Rating methodological quality of studies: CBT studies M = 27.8 (SD = 4.2) ACT studies M = (SD = 5.0).

Criteria for inclusion RCT (13 studies, N = 677) published or in press Published in English Acceptance based

Results an overall mean ES of 0.68 for ACT (13 studies; N = 677) ACT compared to waitlist (2 studies) ES = 0.96 ACT compared to TAU (5 studies) ES = 0.79 ACT compared to an active treatment (two studies comparing ACT to (CT) and one to Systematic Desensitization) ES = 0.53

Overlap with other MA 12 studies included in Hayes (one dissertation now as article) 13 studies included in Powers 1 study included in Veehof 4 studies included in Ruiz 9 studies included in A-Tjak

Powers et al, 2009 Until March 2008 RCT 18 studies (N = 917) Separate analysis for depression (2 studies), physical health (5 studies) and other mental health conditions (7 studies)

Criteria for inclusion RCT Acceptance based treatments mental and physical health disorders Published in English

Results ACT versus all control conditions ES = 0.42 on primary outcome measures ACT versus established treatments ES = 0.18 ACT versus waitlist condition and psychological placebos ES = 0.68 on secondary measures ACT versus TAU ES = 0.42 on secondary measures

Overlap with other MA 12 studies included in Hayes (one dissertation now as article) 12 studies included in Öst 1 study included in Veehof 6 studies included in Ruiz 12 studies included in A-Tjak (one study published in 2012 FU information)

Veehof et al, 2011 ACT and mindfulness Rating methodological quality with an 8-point scale, based on criteria by the Cochrane Collaboration and the validated Jadad scale Until Januari studies, of which 9 RCT, 2 of which are concerning ACT (also in other MA) Chronic pain only

Ruiz, 2012 Until the end of July studies (N= 954) comparing ACT to CBT Not all CBT recognized as such by author(s) outcome or mediation/moderation

Criteria for inclusion Published and unpublished studies outcome or mediation/moderation study comparing full treatments of face-to-face ACT versus traditional CBT Published in English or Spanish

Results ACT better than CBT on primary outcomes (Hedges’s g= 0.40). Post: g+= 0.37 FU: g+= 0.42 no statistically significant differences in depression (g+= 0.27) and anxiety outcomes (g+= 0.14) between ACT and CBT supports the hypothesized mediators suggested in the ACT model

Overlap with other MA 5 studies included in Hayes 4 studies included in Öst 6 studies included in Powers 7 studies included in A-Tjak

A-Tjak et al submitted Michelle Davis, Southern Methodist University Nexh Morina, University of Amsterdam Mark Powers, Southern Methodist University Jasper Smits, Southern Methodist University Paul Emmelkamp, University of Amsterdam

Until March RCT, N = Methodological quality measured a mean score of for ACT studies (SD = 4.96) on the methodology rating scale

Criteria for inclusion RCT, acceptance based treatments Published or retreivable information Only clinically relevant populations: psychiatric or medical diagnosis or high score on relevant psychological questionnaire, treatment seeking/needing at least 10 participants in the active condition(s) at post treatment

Results on primary outcomes ACT outperformed control conditions (39 studies, N = 1.818) Hedges’s g = 0.70 waitlist and psychological placebos (14 studies, N = 583) Hedges’s g = 0.74 TAU (14 studies, N =509) Hedges’ g = 1.13 established treatments (i.e., CBT, CT, or HBE) (7 studies, N = 401) Hedges’s g = 0.07, non significant

Results on secondary outcomes ACT was superior to control conditions (34 studies, N = participants) Hedges’s g = 0.44 life satisfaction/quality measures (14 studies, N = 731) Hedges’s g = 0.60 process measures (16 studies, N = 733) Hedges’s g = 0. 86

Results per group of conditions ACT was superior control conditions for anxiety/depression (8 studies, N = 378 ) Hedges’s g = 1.35 For addiction (8 studies, N = 501) Hedges’s g = 0.35 For somatic complaints (15 studies, N = 682) Hedges’s g = 0.62 For other mental disorders (8 studies, N = 258) Hedges’s g = 0.86

Mean A-Tjak**Mean Ost* ACT CBTDBT 1Clarity of sample description1,711,231,621,54 2Severity/ chronicity of the disorder1,411,311,731,54 3Representative-ness of the sample1,681,081,731,46 4Reliability of the diagnosis0,660,151,320,77 5Specificity of outcome measures1,901,772,001,77 6 Reliability and validity of outcome measures1,901,542,001,23 7Use of blind evaluators0,540,310,580,77 8Assessor training0,390,310,770,69 9Assignment to treatment1,070,851,191,00 10Design0,951,231,621,15 11Power analysis0,270,000,380,15 12Assessment points1,070,921,270,77 13 Manualized, replicable, specific treatment programs1,441,541,691,54 14Number of therapists0,900,231,080,77 15Therapist training/ experience1,200,691,420,92 16Checks for treatment adherence0,760,150,920,31 17Checks for therapist competence0,780,000,230,00 18Control of concomitant treatments0,490,231,000,23 19Handling of attrition1,390,851,190,62 20 Statistical analyses and presentation of results1,881,692,001,54 21Clinical significance0,660,691,040,31 22Equality of therapy hours0,831,551,860,36 TOTAL23,8818,3227,8019,40 * ICC for the total score.92. **ICC for the total score =.99 Methodological Rating Scale Ost (2008)

Overlap with other MA 8 studies included in Hayes 8 studies included in Öst 11 studies included in Powers 7 studies included in Ruiz 22 studies included in no other MA

untiloutcome analysisstudyparticipants Hayes et al, 2006spring 2005Average effect sizes17704 Öst, 2008mid 2007Meta analysis13677 Powers et al, 2009march 2008Meta analysis18917 Veehof et al 2011Januari 2009Randomized and/or controlled239 Ruiz, 2012July 2012Meta analysis16954 A-Tjak et al, submittedMarch 2013Meta analysis form of informationtreatmentpopulation Hayes et al, 2006(un)publishedacceptance bases or single interventionbroad Öst, 2008 published or in pressacceptance basedmental health Powers et al, 2009 published or in pressacceptance basedmental health Veehof et al 2011 published or in pressACTchronic pain Ruiz, 2012(un)publishedACT vs CBTbroad A-Tjak et al, submitted(un)publishedacceptance baseddiagnosable mental health Comparison of aspects of MA

all controlwaitlist, placebo/ TAUstructured interventions C(B)T/established treatments Primary measuresgeneralpostFUgeneralpostFUgeneralpostFUgeneralpostFU Hayes et al, Öst, /0.79 Powers et al, Ruiz, A-Tjak et al, submitted / Comparison on primary and process measures all controlwaitlist, placebo, TAUstructured interventions C(B)T/established treatments Process measuresgeneralpostFUgeneralpostFUgeneralpostFUgeneralpostFU Hayes et al, 2006 Öst, 2008 Powers et al, 2009 Ruiz, 2012 A-Tjak et al, submitted0.86

all controlwaitlist, placebo, TAUstructured interventions C(B)T/established treatments Secundary measuresgeneralpostFUgeneralpostFUgeneralpostFUgeneralpostFU Hayes et al, 2006 Öst, 2008 Powers et al, /0.42 Ruiz, 2012 A-Tjak et al, submitted0.44 Comparison on secundary measures and quality of life all controlwaitlist, placebo, TAUstructured interventionsC(B)T/established treatments Life qualitygeneralpostFUgeneralpostFUgeneralpostFUgeneralpostFU Hayes et al, 2006 Öst, 2008 Powers et al, 2009 Ruiz, 2012 A-Tjak et al, submitted0.60

anxiety/depressiondepressiondistressaddictionsomatic complaintsother mental health Hayes et al, 2006 Öst, 2008 Powers et al, Ruiz, 2012 A-Tjak et al, submitted Comparison per group of conditions